a) Field of the Invention
The present invention relates to a power plug with a freely rotatable delivery point and more particularly to a power plug, wherein a relative angle between insertion terminals and a seat can rotate freely to avoid jump sparks and facilitate operation when rotating the insertion terminals. The power plug includes primarily a plug seat, an interior of which is assembled with an armature and a turntable that is coaxial with the armature. The turntable provides for installation of the insertion terminals, an opposite longitudinal surface between the armature and the seat is indirectly provided with an elastic arch element and plate-typed conducting probes with an elastic shear are indirectly provided between the insertion terminals and the armature. By an elastic stress action between the elastic arch element and the conducting probes, a mechanical vibration wave of motion can be absorbed to avoid gap jump.
b) Description of the Prior Art
A fixed-type power socket is normally located on a vertical wall or a floor of a building to be securely fixed, such that safety can be gained in using an electric appliance and electricity can be extracted for use conveniently. An orientation between an ordinary plug and an electric wire carried by the plug is fixed and an orientation at which the fixed-type socket is fixed into insertion holes on the wall is not changed. Therefore, under a condition that an orientation at which the plug is assembled with the carried wire is fixed, if the plug is inserted at an orientation not conforming to an orientation of electric wiring, an assembly section of the electric wire with the plug will be distorted. In particular, for an electric appliance with a larger demand of electric current, an electric wire carried by the power plug is coarser, which results in a larger mechanical stress, such that it will be difficult to carry out insertion and wiring or even that a plate-typed insertion terminal needs to be bended. The aforementioned shortcomings also apply to an electric appliance, such as a vacuum cleaner or an electric tool, as a location of which needs to be changed constantly, thus a working direction is also changed constantly. As a result, the assembly orientation of the plug and the electric wire carried by the plug should be able to be changed freely, such that the assembly end of the electric wire with the plug can be prevented from distortion.
Regarding to an ordinary design for adjusting the orientation between the insertion terminals of the plug and the carried electric wire, the orientation between the plug seat and the insertion terminals can be changed by indirectly providing the armature between the insertion terminals and the seat, such that the orientation of electric wiring can be altered. There is another rotatable plug, wherein a casing is directly formed with a groove and after a ring-shaped conducting plate is assembled, a surface layer of the conducting plate can provide for connection with the insertion terminals. In addition, the seat is directly provided with an inter-layered armature which conducts electricity to each terminal by layers to explicitly divide positions of energizing, thereby avoiding mechanical deformation of the terminals to result in short-circuiting. Furthermore, there is a layered conducting structure which is assembled coaxially, with each layer providing electricity to each respective terminal, so as to achieve an application of the layered armature.
However, for conducting electricity, whether contact between conducting elements is tight and solid or not will directly affect an efficiency of transmitting the electric current. If the contact is inherently imperfect or a jump occurs when a gap is caused by a vibration wave which is produced when the orientation is changing, then resistors will generate heat or jump sparks will be formed, causing an unnecessary loss. The best solution is to directly connect between the electric wires, without having indirect structures. Yet, considering that the orientation between the plug and the electric wiring should be freely adjustable, it will require elements of relative motion to conduct the electric current indirectly. Therefore, the contact between the indirect elements has to be assured, so that the electric current can pass through a better path, stable energizing can be provided when the plug is moving and jump sparks can be prevented.